Pulmonary Embolism Support Group
By far the most common form of pulmonary embolism is a thromboembolism, which occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. Symptoms may include difficulty breathing, pain during breathing, and more rarely circulatory instability and death.
I've been tested three times and I'm also negative for everything. I have a study somewhere that says that 1/3 of clotters don't have any currently identifiable disorders. Although, since they're learning new things every day, there could be more information down the road.
Of course, you may have just had a perfect storm of events and got "lucky." Not everyone who has a clotting disorder clots.... and not everyone without one (as is obvious) doesn't.
I was tested after my second DVT (twice) and since everything was negative, I came off at six months.
I was tested again after my PEs, although at that point it didn't matter, since I'd be staying on warfarin for life.
It might not necessarily be the meds that are making you feel tired and light-headed. PEs will do both of those things (the exhaustion I felt after my PEs was unlike anything else I've ever experienced). I also had a lot of dizziness and light-headedness, although it turns out those were related to something else.
On average, people stay on the thinners for six months after a first clotting experience. It changes, of course, if you have genetic issues and/or additional clots.
I'd be cautious about coming off the blood thinners too soon. If I remember, you're not sure what caused your clots. It could have been some weird combination of events (car ride, dehydration, being sick, ankle/foot injury, etc.) that caused them and you want to make sure your body is well past that before you come off the thinners. The meds also will help your body heal by making sure that the existing clots don't get any larger and giving your body time to dissolve them.
Six months is pretty standard for first-time clotters, regardless of the cause and situation. Many people stay on for longer, due to previous clotting incidents, cautious doctors, and clotting disorders.
Don't assume that just because you're negative for clotting disorders, you're safe to come off the thinners early. I mean, you clotted once and you could do it again if you don't go through the whole treatment. Better safe than sorry...